A method of solvent-enhanced dye diffusion in polymer films for organic light-emitting diode (OLED) application is introduced. After an initial dye transfer from a dye source substrate into the top of the device polymer film, the device substrate is then exposed to solvent vapor. Due to solvent absorption by the polymer film, the glass transition temperature of the polymer is significantly decreased which leads to enhanced diffusion of the dye in the polymer film. Secondary ion mass spectroscopy and depth dependent photoluminescence show that the temperature for dye diffusion can be decreased by at least 100°C, to room temperature. OLEDs with 0.6% external quantum efficiency have been demonstrated with this method using the polymer poly(9-vinylcarbazole) combined with electron transport molecules and the dyes coumarin 47 and coumarin 6.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy (miscellaneous)